3 .Lymphatic system Flashcards
What is lymph
-A colourless fluid containing WBC
-drains through the lymphatic system into the bloodstream
Lymphatic system functions.
-collect excess tissue fluid from fluid around cells and return it to the cv system
-immune response
-absorbs fat (via lacteal) from the digestive system & transports it to the CV system
Function of lymph
Transports wastes & filters debris to & from the cv system.
What is Plasma
Fluid component of blood
Function of plasma
Transports nutrients & wastes via the blood around the body
What is tissue fluid
Fluid surrounding tissue that leaks out of the cardiovascular system due to increased pressure
Function of tissue fluid
-Supply cells with a stable environment
-provides nutrients such as oxygen for tissues.
Pathway of fluid starting at the cv system
Cv systems→leaks out→ collect tissue fluid →lymph capillaries → lymph vessels→ lymph nodes→ thoracic duct→cv system
Structure of lymph capillaries
-thin single epithelial cell wall
-overlapping epithelial cells→creates gaps
-interlaced with arterioles, venules, and capillary beds of the CV system
-closed at one end→end terminals
How does thin, single epithelial cell wall assist the lymph capillaries function
Tissue fluid can easily pass into the lymphatic system
How does overlapping epithelial cells assist in lymph capillaries function
Allows fluid to move IN to capillary but prevents back flow OUT of capllary
How does the interlacing with arterioles etc assist in the lymph capillaries function
Cv system can Easily access and collect excess fluid
Lymph vessels structure
Valves→prevent backflow
Larger then capillaries→carries lymph from capillaries to ducts
3 key lymphatic vessels
Large lymph vessels
Thoracic duct
Right lymphatic duct
Describe Large lymphatic vessels
Run along most major arteries and veins
Describe Thoracic duct
Drains lymph from both legs, abdominal, and pelvic cavities, the left half of the thorax, head, neck, and left arm
Describe Right lymphatic duct
Drains lymph from the right half of the thorax, head, neck, and right arm
What are primary lymphoid tissue
Sites where lymphocytes are formed and mature
Examples of primary lymphoid tissue
Bone marrow
Thymus
What is Secondary lymphoid tissue
Sites where lymphocytes interact and filter extra cellular fluid
Examples of secondary lymphoid tissue
Lymph nodes
Spleen
Payers patches
Tonsil
What does the thymus do
Mature T cells
Bone marrow function
Create B and T lymphocytes
Mature B lymphocytes
Which of the secondary lymphoid tissues Filter
Lymph nodes and spleen
Which of the secondary lymphoid tissues DESTROY
Tonsils/ adenoids
Peyers patches
What is structure of lymph nodes
-Small clustered lumps of specialised tissue along lymphatic vessels
-contain large amounts of lymphocytes, phagocytes and natural killer cells
Lymph nodes function
-Filter lymph fluid as it is returning to the CV system
-remove foreign particles and break them down
-site of antigen presentation
What are the MALT tissues
Tonsils
Peyers patches
Structure of the spleen
Found in the left hypochondriac region
Consists of red and white pulp
Functions of the spleen
Filters blood
Controls the levels of RBCs, WBCs and platelets in blood
How does the spleen filter the blood
Removes viruses, bacteria and other foreign particles
How does the spleen controls the levels of RBCs, WBCs and platelets
White pulp makes white blood cells
Red pulp removes old, damaged and dead RBCs
Tonsils structure and function
Structure: Found in the mouth and back of throats
Function: destroy inhaled antigens/ pathogens
Peyers patches structure and function
Structure: found in the small intestine
Function: destroy ingested/ swallowed antigens/pathogens
How does lymph move
-valves that prevent back flow
-muscle pump by relaxation and contraction results in the ‘milking action’
-changes in thoracic pressure during respiration
-smooth muscle lining vessel walls contract
What is lacteal and what’s its function
specialised lymphatic capillary on vili of small intestine
–>absorbs digested fats from small intestine
